1. Field of the Invention
This invention relates to a current sensor for detecting an electric current by utilizing a Hall effect, and more particularly to a current sensor having a temperature detection function.
2. Related Art
Hall elements for outputting a voltage corresponding to the magnitude of a magnetic field have heretofore been extensively used in current sensors, and in such a current sensor, the amount of current is detected from the magnitude of the magnetic field generated in proportion to the current.
In automobiles, a current detection is effected by the use of a current sensor, for example, in order to monitor the charging/discharging of a battery or to control a drive motor.
In automobiles, the temperature of a battery, a motor or others is measured, and an ECU controls such a device into an optimum condition based on the measured value (see JP-A-2004-254491, JP-A-2003-209935 and JP-A-2006-46576).
JP-A-2001-272422 discloses a current detection apparatus for a vehicle in which a current path for a temperature detection element is formed utilizing a board of a current sensor on which a Hall element is mounted. As shown in FIG. 8, this apparatus includes the current sensor 12 supported on a bus bar 14 connected to a terminal 17 of a battery 13, and the temperature detection element 20 retained by the bus bar 14.
The current sensor 12 comprises a core 32 of a C-shape (i.e., an O-shape part of which is removed or notched to form a gap), the Hall element 33 disposed in the gap of the core 32, the board 31 on which the Hall element 33 is mounted, and a case 29 housing these parts. The core 32 collects magnetic flux from an electric current flowing through the bus bar 14, to a connector 18 and a cable 16, and forms parallel flux (which is proportional to the magnitude of the current) in the gap. The Hall element 33 converts the magnitude of this magnetic flux into voltage. A connection wire 15 of the temperature detection element 20 is connected to the board 31 of the current sensor 12.
In this apparatus, the current sensor 12 and the temperature detection element 20 can have a common minus-side current path on the board 31, so that the construction of the circuit is simplified.
However, in the temperature detection function-incorporating current sensor disclosed in JP-A-2001-272422 Publication, it is necessary to additionally provide the temperature detection element 20 for the purpose of detecting the temperature, and besides an operation for connecting this temperature detection element 20 to the board 31 is required. Therefore, the apparatus increases in size, and the time and labor required for the production creases, so that the cost also increases.